JP3064394B2 - Magnetic recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a video tape recorder, and more particularly to a method for increasing the deterioration of a recording signal even when a magnetic tape is repeatedly edited and dubbed. And a magnetic recording apparatus which does not cause color blur on reproduced images.

[Prior Art] FIG. 1 (a) shows an example of a magnetic recording apparatus according to the present invention.
(B) Recording system REC of VCR (HDVTR) for HDTV
And the configuration of the playback system PB corresponding to this.

The operation of the recording REC of the HDVTR shown in FIG. 1A will be described.

The baseband recording luminance signal Y is converted to a digital signal by an analog / digital signal conversion circuit (ADC) 1 at a predetermined sampling clock, and is selectively switched by a switch circuit 4 to expand the time axis. The time axis is extended at 7, 8. The recording color difference signal P _B of the baseband, P _R is converted into a digital signal at a predetermined sampling clock ADC2,3, is the signal by the signal inversion circuits 5 and 6 reversed, later in a sequential signal processing circuit 10 a color difference line Then, the data is subjected to a line-sequential vertical filtering process, and further subjected to time axis compression by time axis compression circuits 11 and 12.

The recording luminance signal Y subjected to the time axis expansion processing and the recording color difference signals P _B and P subjected to the line sequential processing and the time axis compression processing
_R is shuffled by the frame memory 14 to generate a video recording signal in the form of a TDM signal of channels A and B in which the luminance signal and the color difference signal are integrated. The synchronizing signal SYNC and the burst signal BURST from the synchronizing signal generating circuit 15 are added to the channel video recording signal in the form of the TDM signal in the signal adding circuits 16 and 17, and the digital / analog signal converting circuits (DAC) 18 and 19 The signal is converted into an analog signal, and is recorded on the magnetic tape 25 via the analog signal processing circuits 20 and 21 and the recording head 23. Analog signal processing circuits 20, 2
1 performs low-pass filtering, emphasis processing, FM modulation, and the like. Playback system PB of HDVTR device shown in Fig. 1 (b)
The operation of is described. The circuit configuration and operation of the reproduction system PB are basically opposite to those of the recording system REC.

The video signal recorded on the magnetic tape 25 is read by the reproducing head 30 and applied to the analog signal processing circuits 32 and 33 via the switch circuit 31. The analog signal processing circuits 32 and 33 operate in reverse to the analog signal processing circuits 20 and 21 in the recording system REC.
For example, FM demodulation and de-emphasis processing are performed. The outputs of the analog signal processing circuits 32 and 33 are converted into digital signals by the ADCs 34 and 35, and the frame memory 36 performs a deshuffling process reverse to the shuffling process of the frame memory 14.

The luminance signal read from the frame memory 36 is subjected to time axis compression processing in time axis compression circuits 37 and 38, and one of the time axis compression processing signals is delayed by 1H in a 1H signal delay circuit 39, and time axis compression is performed in a switch circuit 40. The signal from the circuit 37 and the signal from the 1H signal delay circuit 39 are switched, and the DAC 50 generates a reproduction luminance signal Y corresponding to the recording luminance signal Y. The color difference signals read from the frame memory 36 are subjected to time axis expansion processing by time axis expansion circuits 42 and 43. One of the time axis expansion processing signals is further delayed by a 1H signal delay circuit 44, and these signals are switched by a switch circuit. The signal is switched at 45, applied to the color difference line sequential signal interpolation circuit 46, and the signal is inverted at the signal inversion circuits 47 and 48.
The signals are converted to analog signals by the DACs 51 to 52 and are used for recording color difference signals P.
_B, reproduction color difference signal P _B corresponding to the P _R, P _R is reproduced.

FIG. 3 shows a conventional circuit configuration of the color difference line sequential signal processing circuit 10 shown in FIG. 1 (a). The color difference line sequential signal processing circuit 10 shown in FIG. 3 is composed of a 2H line memory 1 constituting a latch circuit 101, 102, a switch circuit 103, and a vertical filter circuit 10A.
05, signal adding circuit 106, coefficient multiplying circuit 10 multiplying by 1/2 coefficient
7, a signal adding circuit 108, a 1H line memory 109, and a coefficient multiplying circuit 110 for multiplying by a 1/2 coefficient are configured as shown in the figure.

FIG. 4 shows a signal processing form in each part of the color difference line sequential signal processing circuit 10 of FIG. The signals S101 and S102 from the latch circuits 101 and 102 are alternately switched every 1H by the switch circuit 103 to obtain signals S103 and S104. The fourth
Reference numerals in the figure, for example, "41B" is 41H-th color difference signal P _B, "41R" indicates the 41H-th color difference signals P _R.

Chrominance switched to these alternating signals P _B, P _R are stored in the 2H line memory 105 and 1H line memory 109 constituting the vertical filter circuit. This vertical filter circuit 10A
Centering on the color difference signal of a horizontal line (referred to as a reference line) from the H line memory 109, the vertical color difference signals of the horizontal lines above and below the center line are filtered. That is, the color difference signal of the horizontal line below the reference line and the color difference signal of the horizontal line above the reference line from the 2H line memory 105 are added by the signal addition circuit 106, and the coefficient multiplication circuit 1
07 is halved, and this signal is added to the signal adding circuit 108 for 1H.
The color difference signals of the reference line from the line memory 109 are added and halved by the coefficient multiplying circuit 110. FIG. 4 shows signals S103, S104, and S110 obtained by the above signal processing.
The signal S110 indicates the signal subjected to the line sequential vertical filtering. For example, the vertical filtering signal 43B 'is calculated as follows.

43B '= ((42B + 44B) / 2 + 43B) / 2 The signals subjected to the line-sequential vertical filtering processing are subjected to the time axis compression processing by the time axis compression circuits 11 and 12 illustrated in FIG. , Are shuffled by the frame memory 14, FM-modulated, and recorded on the magnetic tape 25.

The color difference line sequential signal interpolation circuit 46 in the reproduction system PB of the HDVTR apparatus shown in FIG. 1 (b) has an inverse circuit configuration to the color difference line sequential signal processing circuit 10 as shown in FIG. That is, the color difference line-sequential signal interpolation circuit 46 includes a 1H line memory 461, a 2H line memory 462, a signal addition circuit 463, a coefficient multiplication circuit 464 for multiplying by a factor of 1/2, and a switch circuit 465, which constitute the interpolation filter circuit 46A. They are connected as shown. The interpolation filter circuit 46A has an inverse circuit configuration of the vertical filter circuit 10A described above with reference to FIG.

FIG. 6 shows the signal form in FIG. The signal S45 that has been subjected to the time axis expansion process illustrated in FIG. 1B and switched by the switch circuit 45 is delayed by 1H from the 1H line memory 461 illustrated in FIG. 6 and output to the switch circuit 465 as the signal S461. The signal S45 is 2H in the signal addition circuit 463.
It is added to the signal delayed by 2H in the line memory 462, halved by the coefficient multiplication circuit 464, and output to the switch circuit 465 as a signal S464. These signals are switched via the switch circuit 465 to obtain interpolation signals S465 and S466. B ″,
R ″ indicates a signal obtained by further interpolating the vertical filtering signals B ′ and R ′ recorded on the magnetic tape.

FIG. 7 shows the signal form of the recording / reproducing process described above.

As shown in FIG. 7A, the color difference signals P _B and P _R having the amplitude of 100%.
When is applied to the recording system REC, the color change is spread in the vertical direction of the screen as shown in FIG. 7B by passing through the vertical filter circuit of the color difference line sequential signal processing circuit 10 described above. The signal of FIG. 7B recorded on the magnetic tape 25 is reproduced by the reproduction system PB in a signal form as shown in FIG. 7C.
P _B, is reproduced P _R. That is, the color difference signals P _B and P _B are passed through the interpolation filter circuit of the color difference line sequential signal interpolation circuit 46.
Each change of _R spreads in the vertical direction of the screen. In FIG. 7, * indicates an interpolation signal obtained from the preceding and following lines.

[Problems to be solved by the invention]

Using the HDVTR device that performs signal processing as described above, editing and dubbing of a video signal once recorded are repeated.
There is a problem that the recorded video signal deteriorates and the color blur of the reproduced image is accumulated.

For example, from the magnetic tape recorded by the above process
When dubbing is performed using an HDVTR device, the HDVTR device reproduces a color difference signal shown in FIG. 7C and records the data on a magnetic tape by a recording system REC based on the color difference signal. This recording signal has a signal form shown in FIG. 7 (d). That is, during dubbing, the waveform again passes through the vertical filter circuit of the recording system REC, causing further waveform deterioration as shown in FIG. 7 (d). When this waveform is reproduced, the waveform further deteriorates as shown in FIG. 7 (e). reproduction color difference signal P _B, the P _R.

When dubbing or editing is repeated in this manner, the deterioration of the recorded video signal increases, and the color blur of the reproduced image increases.

As described above, the HDVTR device has been exemplified, but the same problem occurs in other devices that perform filtering processing of the video signal and record and reproduce the video signal.

Therefore, an object of the present invention is to solve the above-mentioned problem with a simple circuit configuration.

[Means for solving the problem]

According to the present invention, there is provided a magnetic recording apparatus which performs line-sequential filtering on a color signal in a direction orthogonal to a plurality of horizontal scanning lines, compresses the time axis, and records it on a recording medium together with a luminance signal. A circuit for performing filtering includes a 2H line memory connected to a first input terminal and a 1H line memory connected to a second input terminal, and a first circuit for adding an input signal and an output signal of the 2H line memory. , A first coefficient multiplication circuit, and second addition means for adding the multiplication result of the first coefficient multiplication means and the output of the 1H line memory. Filter means for filtering the color difference signals of the preceding and succeeding frames based on the recorded color difference signal, and switching between the first and second color difference signals for each 1H, the switched first color difference signal and the second color A first switching means for alternately inputting a signal to the second H line memory and the 1H line memory of the filter means, and outputting a filter processing result of the filter means in a first operation mode; 1H in operation mode
And a second switching means for outputting the output of the line memory.

[Action]

The first switching means switches the first and second color difference signals line-sequentially and outputs the signals to the 1H line memory and the 2H line memory of the filter means.

The filter means performs filter processing with the color difference signals of the preceding and succeeding frames, that is, filter processing in the vertical direction, based on the color difference signals of one frame stored in the 1H line memory.

The second switching means outputs a filter processing result of the filter means in, for example, a first recording mode which is a normal recording mode, and outputs the filter processing result in a second recording mode which is a mode for performing dubbing or editing, for example. The output of the 1H line memory that does not perform filter processing is output as it is. In the second recording mode, a new recording signal does not deteriorate due to the filtering process, so that the above-described increase in the color blur of the reproduced image does not occur.

The process of filtering the color signals in the direction to be directly sent to a plurality of horizontal scanning lines, compressing the time axis, and recording them on a recording medium together with the luminance signal is the same as the conventional process.

〔Example〕

FIG. 2 illustrates the above-described HDVTR apparatus of FIG. 1 as an embodiment of the magnetic recording apparatus of the present invention.

In the present invention, the color difference line sequential signal processing circuit shown in FIG.
10 is configured as shown in FIG.

In the circuit of FIG. 2, a switch circuit 111 is added to the conventional color difference line sequential signal processing circuit 10 shown in FIG. The switch circuit 111 receives the signal S110 of the coefficient multiplication circuit 110 of the vertical filter circuit or the signal from the 1H line memory 109.
Switch S109. In the normal recording mode, the switch circuit 111 outputs a signal from the contact N connected to the output of the coefficient multiplying circuit 110. In the dubbing or editing mode, the signal from the contact E connected to the 1H line memory 109 is output. Is output.

The signal processing in the normal recording mode is as described above in the description of the prior art with reference to FIG.

Not vertical filtered in edit mode
A signal from the 1H line memory 109 is output. Therefore, in this case, deterioration of the conventional recording signal caused by passing through the vertical filter circuit 10A does not occur. Since the reproduced color difference signals have been subjected to vertical filtering, the vertical filtering may not be further performed in the edit mode.

As a method of bypassing the vertical filtering process, the 1H line memory 109 itself may be bypassed as shown by a broken line in FIG.

Note that since the above-described vertical filtering processing is not performed on the luminance signal Y, the above-described signal deterioration does not occur and the bypass processing is unnecessary.

The vertical filtering process for three horizontal lines has been described above. However, the present invention can be applied to the vertical filtering process for a plurality of horizontal lines.

Although an HDVTR device has been illustrated, the present invention can be applied to a device that performs a line-sequential filtering process on a plurality of color signals such as two types of color difference signals in the same manner as described above.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a magnetic recording apparatus that does not increase the deterioration of a recording signal even when editing or dubbing a plurality of times with a simple circuit configuration. As a result, the color blur of the reproduced image does not increase.

[Brief description of the drawings]

1 (a) and 1 (b) are configuration diagrams of an HDVTR device according to an embodiment of the present invention, FIG. 2 is a vertical filter circuit diagram of an embodiment of the present invention, FIG. 3 is a conventional vertical filter circuit diagram, FIG. 4 is a diagram of the signal processing form according to FIG. 3, FIG. 5 is a diagram of the interpolation filter circuit in FIG. 1, FIG. 6 is a diagram of the signal processing form by the interpolation filter circuit of FIG. 5, and FIGS. (e) is a diagram showing a conventional signal processing mode. (Explanation of reference numerals) 7,8: time-axis expansion circuit, 10: color-difference line-sequential signal processing circuit, 11,12: time-axis compression circuit, 14 ... frame memory, 20,21 ... analog signal processing circuit , 32,33 ... analog signal processing circuit, 36 ... frame memory, 37, 38 ... time axis compression circuit, 42, 43 ... time axis expansion circuit, 46 ... color difference line sequential signal interpolation circuit.

Claims (1)

(57) [Claims] 1. A magnetic recording apparatus for performing line-sequential filtering on a color signal in a direction orthogonal to a plurality of horizontal scanning lines, compressing the time-axis, and recording the color signal together with a luminance signal on a recording medium. A 2H line memory connected to a first input terminal and a 1H line memory connected to a second input terminal, and a first circuit for adding an input signal and an output signal of the 2H line memory. An adding means, a first coefficient multiplying circuit, and a second adding means for adding the multiplication result of the first coefficient multiplying means and the output of the 1H line memory; Filter means for filtering the color difference signals of the preceding and succeeding frames based on the color difference signal obtained, and switching between the first and second color difference signals for each 1H, and the switched first color difference signal and second color difference Faith A first switching means for inputting alternately to the second H line memory and the 1H line memory of the filter means, and outputting a filter processing result of the filter means in a first operation mode; And a second switching means for outputting the output of the 1H line memory in a mode.